This invention relates to a self-propelled agricultural crop harvester such as a combine and more particularly to improvements in frame construction, configuration, and arrangement of functional units in such a machine.
In spite of some sophisticated accretions, for example, in transmission and control systems and some refinements in gathering, threshing and conveying equipment, most current self-propelled combines still betray their origins in the threshing machines of the late 19th century.
However, economic trends are giving rise to an apparently insatiable demand for improvements in labor productivity and field efficiency and larger grain tanks and higher travel speeds are helping to achieve such improvements in performance. Both larger tanks and higher speeds require improved frame design and the limitations placed on overall vehicle size by transport requirements mean that larger grain tanks and stronger frames must be accommodated in a compact form. In some recent machines attempts have been made to rationalize configuration with such objects as reducing overall height, improving stability and convenience of service and repair while increasing grain tank size to match higher harvesting rates. But such attempts have generally been inhibited by the presence of the bulky and inflexible traditional threshing, separating and cleaning mechanisms and machines have tended to remain mobile agglomerations of components, with frames and configurations better suited to static application.
High performance, high capacity combines entail proportionately greater capital investment and potentially greater losses from any interruption of harvesting. Users complain that in current expensive and complex machines repair or replacement of major functional units is often costly or impractical because of the way in which such units are interdependently built into the structure.